The present invention relates to a light emitting diode array in which a large number of light emitting diode pellets are arranged for use in exposure light sources for facsimile, exposure light sources or light sources for removing electric charges on a drum in an electronic copy machine, or light sources for display device etc.
For a light source to optically recognize a manuscript in a transmitting unit of a facsimile, or a charge removing light source to remove electric charges charged on a light sensitive drum of an electronic copy machine, an array on which a large number of light emitting diodes (which will be called "LEDs" hereinafter) has been recently used. A plurality of LED pellets linearly arranged on a base are surrounded by partition members and an outer frame member, and an optically focusing lens is provided at the opening portion of the outer frame member.
Such an array has an arrangement such that the lens is fitted into the outer frame member and is mounted on the partition members. Accordingly, the drawback of such an array is that the height from the bottom of the base to the top of the lens is large, resulting in a large-scale of the array, and that an illumination at an radiation surface is lowered as the distance between the LED and the lens is large when using the LEDs having small quantity of light, although a quantity of light is increased according as the number of LEDs is increased.
Further, in a recent electronic copy machine having a reduction function, it is desired to use a light source having a sharp radiating light beam as a blank exposure light source for removing electric charges in blanks of a paper. However, when the above-mentioned array is applied to copy machine, the radiating light beam spreads too much in an arrangement direction of LEDs. As a result, there arises a problem that the boundaries between light emitting areas and non-light emitting areas become indistinct, resulting in occurence of blurred portions when making a copy.